private static void Add(string machineId, string productName, string productVersion, string edition,
string serialNo, string limit, string expDate, string signature)
{
License lic = new License(productName, productVersion, machineId);
string key = GetKey(machineId, productName, productVersion);
lic.Edition = edition;
lic.Type = License.Commercial;
lic.SerialNo = serialNo;
lic.ExpirationDate = Date.Parse(expDate);
lic.Limit = limit;
lic.Sign(signature);
Dict[key] = lic;
}